Along with the progress of medical technology in recent years, the number of cases has increased where cardiopathy which has been considered as a serious disease can be cured. On the other hand, with respect to serious cardiopathy, at present, there may also be a case where the only way to cure such cardiopathy is with a heart transplant. Under such circumstances, a patient waiting for a heart transplant has to wait for a donor who is compatible with the patient. Accordingly, there may also be a case where the heart transplant cannot be promptly carried out thus causing a serious problem in maintaining the life of the patient waiting for a heart transplant.
Under such circumstances, recently, there has been proposed a method which assists the circulation of blood by embedding an artificial heart in a patient waiting for a heart transplant aiming at BTT (Bridge To Transplant). With the use of such an artificial heart, the patient waiting for a heart transplant can wait for a donor who is compatible with the patient for a long time. Further, at present, due to the enhancement of stability, reliability and the like of an artificial heart, attention has been focused on the use of an artificial heart aiming at BRT (Bridge To Recovery) which allows a patient to seek for the recovery of functions of his own heart. In fact, there have been many reports on cases in which a patient has recovered functions of his own heart by embedding of an artificial heart.
A technique has not been yet established which enhances the recovery of functions of a patient's own heart by the use of an artificial heart aiming at the use of BTR. However, there have been disclosed several artificial heart control techniques necessary for achieving the recovery of functions of the patient's own heart.
For example, patent document 1 discloses an artificial heart which regulates a load applied to a ventricle by providing an afterload regulatory chamber for temporarily storing blood ejected from the ventricle. Patent document 2 discloses, for example, an artificial heart which adjusts a rotational speed of a blood pump in response to a rapid change deviating from a normal operation range of a pump operation state in a continuous flow blood pump. Patent document 3 discloses an artificial heart which paces a ventricle in response to the presence or the non-presence of the occurrence of sticking of a blood removing cannula using a heart pacing function thus maintaining a cardiac rate of the patient's own heart above a certain specified number even at the time of wearing the artificial heart and thereby the sticking of the blood removing cannula, the occurrence of a thrombus and bradycardia or the like can be prevented. Further, for example, patent document 4 discloses a cardiac function evaluating device which evaluates a cardiac function by measuring a blood flow rate in a blood pump. Further, for example, patent document 5 discloses an artificial heart which lowers a rotational speed of a blood pump for suppressing the formation of a thrombus around the aortic valve. Further, non-patent document 1 discloses a technique on computer simulation in which the behavior of a continuous-flow-type blood pump when a rotational speed is changed is modeled.